Abstract: Objective To analyze the relationship between positive direct antiglobulin test （DAT） and efficacy of red blood cell（RBC） transfusion. Methods Medical records of 86 DAT-positive patients accepting RBC transfusion were retrospectively analyzed. The characters including disease type,blood count,DAT-positive type,agglutination intensity and therapeutic impact of RBC transfusion were analyzed,compared with DAT-negative group. Results The common types of diseases in DAT-positive blood transfusion patients were hematological diseases（36,43.37%）,infectious diseases（22,26.51%）,kidney diseases（7,8.43%） and other unknown causes（7,8.43%）. The values of Hb,RBC,and Hct in DAT-positive group were 5.75±3.71（g/L）,0.19±0.14（10¹²/L）,1.65±1.28（%）,whereas the values in DAT-negative group were 8.09±3.57（g/L）,0.24±0.15（10¹²/L）,2.43±1.28（%）. The values in DAT-positive group were lower than that in DAT-negative group,and there were statistically significant differences（P<0.05）. The effective rate of blood transfusion in DAT-positive group（61.48%, 83/135） was significantly lower than that in DAT-negative group（80.74%,109/135）（P<0.01）. By DAT-positive typing,the values of Hb after blood transfusion in IgG+C3d group,IgG group,and C3d group were 8.20±4.65 U,5.73±3.53 U,2.01±2.55 U,respectively. The value of Hb in C3d group was lower than that in negative group（Hb 8.09±3.57 U）,IgG+C3d group and IgG group,and the difference were statistically significant（P<0.05）. The value of Hb in IgG group was lower than that in negative group and IgG+C3d group,and the difference were statistically significant（P<0.05）. The effective rate of blood transfusion in IgG+C3d type （90.00%）>IgG group（61.34%）>C3d group（16.67%）,and the difference were statistically significant（P<0.05）. There was no statistically significant difference in efficacy of different agglutination intensities on RBC transfusion by DAT-positive typing （P>0.05）. Conclusion DAT-positive is common in patients with hematological diseases and infectious diseases. The effective rate of DAT-positive patients decreases after RBC transfusion,which may be related to DAT-positive typing. Blood transfusion indications for DAT-positive patients should be strictly controlled to ensure safe and effective blood transfusion.

Key words: Direct antiglobulin test, Blood transfusion, Transfusion efficiency